The VideoLAN Forums

Posted: **14 Apr 2021 12:59**

Hi! I would like to know if this is a bug or by design.
libvlc_new_media_callbacks:
TS duration - 0 (why?)
mp4 duration - perfectly
mkv duration - perfectly
avi duration - perfectly

libvlc_media_new_path, libvlc_media_new_fd:
TS duration - perfectly
mp4 duration - perfectly
mkv duration - perfectly
avi duration - perfectly

I only use libvlc_new_media_callbacks for local files.

Posted: **14 Apr 2021 16:36**

TS duration is just a rough estimate from file size. Using callbacks, the file size is unknown.

Posted: **14 Apr 2021 21:27**

TS duration is just a rough estimate from file size. Using callbacks, the file size is unknown.

but

Code: Select all

libvlc_media_t* libvlc_media_new_callbacks	(
	libvlc_instance_t * 	instance,
	libvlc_media_open_cb 	open_cb, //<--
	libvlc_media_read_cb 	read_cb,
	libvlc_media_seek_cb 	seek_cb,
	libvlc_media_close_cb 	close_cb,
	void * 	opaque 
)

libvlc_media_open_cb
int(* libvlc_media_open_cb) (void *opaque, void **datap, uint64_t *sizep)
sizep byte length of the bitstream or UINT64_MAX if unknown [OUT]

the file size is known. I assign it to the *sizep argument

Posted: **15 Apr 2021 10:37**

TS need to read some data from start and from end. There's no stored information like MP4 or MKV.
Unsure if the callbacks can provide that.

Posted: **16 Apr 2021 01:20**

TS need to read some data from start and from end. There's no stored information like MP4 or MKV.

Yes, that is right. In my implementation, libvlc_new_media_callbacks has direct access to the file and should also find the duration quickly as if I were opening the file using the path.
I tried to find the code where this condition (pseudocode: IF file is mpeg-ts and used libvlc_new_media_callbacks THEN duration = 0) is, but with no success so far.

The VideoLAN Forums

TS duration is always 0 if use libvlc_new_media_callbacks

TS duration is always 0 if use libvlc_new_media_callbacks

Re: TS duration is always 0 if use libvlc_new_media_callbacks

Re: TS duration is always 0 if use libvlc_new_media_callbacks

Re: TS duration is always 0 if use libvlc_new_media_callbacks

Re: TS duration is always 0 if use libvlc_new_media_callbacks